Social media has lots of benefits, but compared to Christianity, it tends to group people by interests. Religion puts you with people who have nothing in common except that you're human.
The purpose of propaganda is not to provide interesting distraction for blasé young gentlemen, but to convince... the masses. But the masses are slow moving, and they always require a certain time before they are ready even to notice a thing, and only after the simplest ideas are repeated thousands of times will the masses finally remember them.